Unit 4: Origin of Life, Viruses, Bacteria, and Archaea.

"If God didn’t do it this way, He missed a good bet." - Harold Urey (1893-1981). US chemist and winner of Nobel Prize for Chemistry in 1943. This is a remark he made after experiments conducted in his laboratory (the famous Miller-Urey experiments) suggested that molecules in the primitive atmosphere of the earth could have spontaneously united, eventually giving rise to life.

"Comets giveth and comets taketh away." - Carl Sagan (1934-1997), American astronomer and Cornell professor of Astronomy, commenting on the notion that life may have been seeded on earth initially by comets, and that later collisions of comets with Earth caused mass extinctions of life.

Objective 1:

Earth formation hypothesis (1a)
Abiotic formation, accumulation of small organics (1c)
Formation of organic polymers from the ancient oceans (1c)
Snowball Earth^(optional)
More Snowball Earth (optional)

Objective 3:

Protobionts, coacervate droplets, proteinoid microspheres (3a)
An RNA world, ribozymes (3b)
Scientists Debate RNA's Role at Beginning of Life on Earth^(optional)
Was DNA invented by viruses?^(optional)

Objective 4:

Timeline of life
Exploring Life's Origins^(optional)

Objective 6:

Modes of attack, infection: plant viruses v. bacteriophages v. animal viruses (6a)
How do viruses leave host cells? (6c)
Retroviruses & Why is HIV / AIDS so deadly? (6b) ^(optional)

Objective 7:

Anti-viral drugs, why don't viruses respond to antibiotics?
Viruses found to use "hive intelligence" ^(optional)

Objective 9:

Centers for Disease Control and Prevention BSE information
Making Sense of Mad Cow Disease ^(optional)
BSE and vCJD: Instant Expert ^(optional)
Creutzfeldt-Jakob disease: Virus or prion? ^(optional)

Objective 13:

The evolution of complex biochemical pathways
13e/13f: Which came first, cyclic or non-cyclic photophosphorylartion? Why was the evolution of autotrophic pathways necessary for life to continue? What is meant by the term oxygen revolution? Note: nonoxygenic photosynthesis is equivalent to cyclic photophosphorylation.

Objective 16:

Enodsymbiosis and the origin of Eukaryotes^(optional)

SLIDES - Accompanying text can be found in your Survival Manual, pages 72-74.

Virus and Bacteria Slides

Optional Supplementary Material:

• Chinese spice effective in treating bird flu
• Human skin harbours unknown bugs
• Did DNA come from viruses?
• Virus used to track elusive cougars - Could a virus be a natural GPS?
• A helpful virus?
• Can lowly Lactobacillus stop HIV? - A harmless bacterium that binds to the HIV virus may lead to a cheap way to control infection.
• Predicting Bird Flu's Future - Avian flu could be morphing into forms going unobserved by most researchers, if one scientist's theory is correct.
• West Africa goes after Polio - immunization drive launched following 2003 polio vaccine boycott that led to current epidemic in the region.
• Cornell's tiny, vibrating paddle oscillator senses the mass of a virus - new device may lead to virus-detection systems.
• Earth microbes on the moon
• Self-Made Cells Show Life Could Come From Space
• Emerging Diseases:
  • Beating back the next pandemic
• Bacteria/Archaea:
  • Wild Things: The Most Extreme Creatures - One species of bacteria, Deinococcus radiodurans, can withstand a 15,000 gray dose of radiation – 10 grays would kill a human and it takes over 1,000 grays to kill a cockroach.
  • Biohazard lurks in bathrooms: Shower curtains awash with potentially harmful bacteria.
  • Antarctica's extremophile resources at risk
• Talking to bacteria - altered bacteria blink on and off like lightbulbs when doused with a chemical signal
• Prions and Mad Cow Disease (BSE):
  • First mad cow found in America
  • New rules to stop spread of BSE
  • BSE barriers
  • Prions get fishy
  • Gene tweak halts mad cow disease
  • Stopping Prions from Going Mad
  • Science Web Supplement: CJD & Prion Diseases

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